In recent years, a sealed scroll compressor including a partition plate, a compressor unit and a motor unit has been known. In the sealed scroll compressor, a partition plate partitions an inside of a pressure container into a low-pressure chamber and a high-pressure chamber. The compressor unit includes a fixed scroll and an orbiting scroll provided in the low-pressure chamber which is partitioned by the partition plate. The motor unit revolves the orbiting scroll. In this type of the sealed scroll compressor, a boss of the fixed scroll is fitted in a securing hole of the partition plate. A sealed scroll compressor that discharges refrigerant compressed in the compressor unit through a discharge port of the fixed scroll to a high-pressure chamber partitioned by a partition plate is proposed (for example, see PTL 1).
In the scroll compressor represented by the sealed scroll compressor disclosed in PTL 1, the compressor unit is surrounded by a low-pressure space, so that the orbiting scroll and the fixed scroll are forced to separate from each other.
Hence, in many sealed scroll compressors, a tip seal is used to improve sealability of a compression chamber formed between the orbiting scroll and the fixed scroll.
Back pressure however is preferably applied to the orbiting scroll or the fixed scroll to perform an efficient operation. In the sealed scroll compressor disclosed in PTL 2 for example, a back pressure is applied to the fixed scroll to push the fixed scroll against the orbiting scroll. This allows eliminating a tip seal as well as improving sealability of the compression chamber.
FIG. 11 is a longitudinal sectional view illustrating a configuration of a conventional sealed scroll compressor. Pillar member 205 secured by bolt 204 to main bearing 203 is fitted in through hole 202 provided in outer flange of fixed scroll 201, thus supporting fixed scroll 201 in a manner movable in an axial direction.
Bolt 204 securing pillar member 205 to main bearing 203 however might become loose by vibration during an operation, which allows pillar member 205 to move in the axial direction as well as a horizontal direction. This disadvantageously causes a shift of fixed scroll 201, which deteriorates reliability of the scroll compressor.